what is the biggest quantum computer?
Google: 72 bit
Intel: 49 bit
IBM: 20 bit
These are the publicly annouced prototypes, made by the american corporations.in the last year.
No information if they are actually usable (just the annoucements from the corporations itself, no third party verify). Also, there is no puiblic information about quantum computer prototypes outside america, but other prototypes exist as well.